A. Field of the Invention
This invention relates to a ladder base swivel with a water channel and, in particular, to such a swivel having a water seal wherein the seal is in communication with a lubricant reservoir for seal lubrication.
B. Background Art
Aerial ladders such as those used on fire trucks must be rotatable with respect to the fire trucks upon which they are mounted, hydraulically extensible, and capable of delivering water and electric cables for control. Therefore, these ladders must be mounted upon hydraulic swivels which are capable of passing water at high flow rates while rotating without allowing the water to interfere with the hydraulic or electric circuits.
Conventionally, this is accomplished by a swivel having a metal housing and a rotatable body having a water channel wherein channels for hydraulic circuits are formed between the body and the housing and rotatable slip rings provide continuity in the electric circuits. This requires a seal to prevent the water passing through the body of the swivel from leaking and interfering with the hydraulic or the electric circuits.
As an added protection for the electrics and hydraulics, a waterway escape channel, communicating with a waterway escape port, was provided between the seal and the electrics since this seal is subject to eventual wearing, drying, and cracking. Thus, when a seal failed, water was directed through the channel to the escape port and was not permitted to come in contact with the hydraulic or electric circuits. A swivel of this type has previously been manufactured by the present Applicant. However, this swivel had no seal lubrication or other protection for preventing seal failure.
There were several common causes of seal failures in the swivels. One was the eventual wearing, drying and cracking of the seals. Another was the effect of the high mineral content of the water commonly used by municipalities for extinguishing fires. These minerals, in addition to damaging the seal, caused corrosion of the metal body around the seal causing more leakage around the seal, as well as roughening the surface of the metal and wearing the seal more quickly.
It is therefore an object of this invention to prevent hydraulic swivel seals from drying and cracking and to thereby extend their useful lifetime.
It is a further object of this invention to provide lubrication of the water channel seals in an hydraulic swivel to lessen the wear caused by rubbing.
An additional object of this invention is to provide a lubricant coating to the metal surfaces in the vicinity of the seal and to thereby inhibit the corrosion of the surfaces by mineral-laden water and the consequent wear of the seal.